Due to the increasing popularity of video streaming services over Internet, the traffic volume on the transit or the peering links continues to grow. Many recent research activities have addressed the locality of content delivery from network edge by introducing storage module into routers. With a persistent Request-Routing System that can redirect all the requests for the same content to a particular content router in order to consume a single multicast stream only during the prefix length of that content, this letter proposes the hybrid Content Delivery Network (CDN) system, which successfully combines novel content routers in underlay with existing CDN servers in overlay by employing prefix caching and multicast schemes respectively. Given the capacity of CDN server, we evaluate and compare the performance of two multicast schemes for the delivery cost minimization in terms of optimal prefix length with in-network caching in the proposed system.